Insulation-joint.



M frz ames A. MOLEAN. INSULATION JOINT.

APPLIUATION FILED JUNE 11, 1909.

960,377., Patented June 7,1910.

ANDREw a. mamma Co PHOTO-UWOGMPNERS. wAsmNG'TaN o t;

ANDREW IVIGLEAN, OF DETROIT, MICHIGAN.

INSULATION-JOINT.

Specification of Letters Patent.

Patented June 7, 1910.

Application filed June 11, 1909. Serial No. 501,624.

To all whom t may concern.'

Be it known that I, ANDREW MOLEAN, a subject of the King of GreatBritain and Ireland, residing at Detroit, in the county of Wayne andState of Michigan, have invented certain new and useful Improvements inInsulation-Joints, of which the following is a specication, referencebeing had therein to the accompanying drawings.

The invention relates to insulation joints or couplings for use inconnection with electric or combination fixtures, and designedespecially for uniting the fixtures to either the ordinary gas pipe ofthe house, or, in straight electric work, to a special met-allieconduit, and it consists in the novel and simple construction of thecoupling or joint, in the peculiar arrangement and combination of itsparts, and in certain details of construction, as will be hereinafterpointed out.

In the drawings,#Figure 1 is a vertical central section through aninsulation joint or coupling embodying my invention; Figs. 2 and 3 aredetached perspective views of the coupling members; and Fig. 4L is asectional view, showing a modified form of coupling.

In Figs. 1 to 8 inclusive a construction of coupling is shown especiallydesigned for what is generally termed straight electric work. In thesefigures, the reference-letter A designates the projecting portion of anordinary gas pipe, having an externally threaded end B.

C represents the coupling in its entirety, screwed upon the pipe end, asshown, and having a threaded bearing at its lower end adapted to engagethe pipe of the fixture, or, if desired, a hook-carrying plug on which achain or other similar device may be placed.

In construction, the coupling comprises a tubular section D internallyscrew-threaded, as at E, to engage the pipe, formed with a cylindricalhead F, and an intermediate elongated frusto-conical section Gr, thefunction of which will be hereinafter set forth.

I-I represents a complementary section arranged in axial alinement withthe member D, formed with an externally threaded head I and aninternally threaded tubular portion J.

K designates a coupling, in the form of a sleeve uniting the parts,insulated from the upper section, and having an internal thread M formedwithin its lower end engaging the external thread upon the lowercoupling or joint member.

It is desirable in joints or couplings of the character described toprovide an interlocking engagement between the axially alining members,first to permit of the rotation of either of the members in screwing thecoupling upon the gas pipe without relative movementof the other, whichallows the application of a wrench upon the outer section or couplingmember when it is inconvenient to apply the tool to the complementarymember; and, secondly, to prevent the insulation between the membersfrom being injured. It is also desirable to employ as the insulatingmaterial sheets of mica, which is the most satisfactory and effective inuse, and to permit of the use of such material I provide a peculiar formof joint betwen the parts which will allow the mica to lie flat in sheetform, thus preventing its breaking or cracking.

The meeting faces upon the heads of the sections D and H are formedflat, as shown in Figs. 2 and 3, designated by the reference letters Oand P, and are arranged in planes oblique to the longitudinal axis ofthe coupling, as plainly shown in Fig. 1. This angular facing of theheads preventswhen the parts are assembled-independent rotation betweenthe members, and at the same time affords a flat surface upon which themica sheet may rest.-

Q represents the insulation referred to, extending marginally beyond thehead F, the latter being of less diameter than the head I, so as toguard against contact between its periphery and the coupling sleeve.

R represents insulation material, preferably a mica washer, interposedbetween the tapered portion S of the coupling sleeve and acorrespondingly tapered or conical surface Gr on the member D.

The insulations described properly insulate the electric fixture fromthe supporting conduit, while the layer of insulating material Q serves,in addition, to seal the pipe and prevent the escape of gas.

From the foregoing description, it will be readily seen that inassembling the parts the coupling sleeve K which unites the jointmembers is self-centering, by reason of its tapered end portion and thefrusto-conical surface that this tapered portion engages. Thus, thedepending internally threaded portionlof the sleeve is properlypositioned I in relation to the head section F of the mem-v ber D, so asto leave a sufficient annular space F to guard against contact betweenthe sleeve and the head short circuit.

placed ground mica, or other insulating material, if desired; also, Ipreferably make the thread Mof the coupling sleeve a lefthand thread, sothat in applying the coupling to the conduit the rotation of the latter.

by the application of the wrench or other tool to the coupling sleevewill have a tendency to more tightly clamp the coupling members togetherupon the insulating material.

In Fig. 4 I have illustrated the form of joint or coupling designed forcombination work. This construction is similar to that alreadydescribed, with the exception that the mica insulation between thecoupling members is apertured, as at A, to permit of the iow of the gas-into the fixture.

' What I claim as my invention is,-

l. An insulation joint for electric fixtures, comprising a headedtubular section adapted to be screwed upon a gas pipe, a similar sectionin axial alinelnent with the first-mentioned section, the section headsadjoining and having flat meeting faces oblique to the longitudinal axisof the joint and insulated one...from the other, and a coupling unitingthe sections and insulated from the section connecting with the gaspipe.

2. An insulation joint or coupling, comprising complementary tubularheaded members arranged in axial alinement'with the and the` resulting Yjacent toits head, a self-centering coupling sleeve having a taperedportion embracing the frusto-conical section, and an internally Withinthe space F referred to 4may be threaded end screwed upon the head ofthe adjoining section, and insulating material between thefrusto-conical section Vand the vtapered portion of the sleeve.

3. In an insulation joint or couplingfor electric fixtures, thecombination with a tubular member internally screw-threaded at one endto'engage a gas pipe, terminating in la cylindrical head at the other,and formed intermediate itsends with an external frusto-conical section,a second tubular member adjacent to and axially alining wit-h the first,the meetingrportions or faces of the members extending in obliqueVangular relation to the longitudinal axis of the coupling, a flat layerof mica linterposed between the meeting'faces, insulating the membersand sealing the gas pipe, a coupling sleeve having a screw-threadedengagement with said second member, and a ta- In testimony whereof Iaflix my signature A v in presence of two witnesses. y

ANDREV MCLEAN.

Witnesses: 1

NELLIE KINSELLA, W. J. BELKNAP.

